i have a 20KW Generator 1 phase set up as 3 wire my hose has a 4 wire plug in for the generator. i have no idea how to hook this one up to make it work correctly the Gen has 3 lugs 2 red and a black the cord that was with it is a 4 wire but the white is cut and not used it only uses the red black and green .my old generator had a 4 wire plug and that is what the hose was set to use for my old generator can i just change the plug on the new cord? or do i need to change the outlet in the house?

any help is welcome

thank you